System management method for a data center

ABSTRACT

Changes such as addition or removal of a device in a system composed of a number of devices are automatically detected and the physical location of the devices is managed. A management method of this invention includes a step (S 502 ) of detecting the physical location of servers (S 1  through S 3 ) connected to a network switch ( 2 ) that is to be monitored, steps (S 512  and S 513 ) of collecting a globally unique MAC address which is unique to equipment of the servers (S 1  through S 3 ) connected to the network switch ( 2 ) and is not shared by the equipments, and a step (S 517 ) of creating configuration information from the MAC address and from the physical connection location of the network switch ( 2 ).

CLAIM OF PRIORITY

The present application claims priority from Japanese application JP2003-384985 filed on Nov. 14, 2003, the content of which is herebyincorporated by reference into this application.

BACKGROUND

This invention relates to a method of centralizing management of anumber of computers and network devices, and more specifically to animproved method of managing a number of devices for a data centerautomatically.

In a computer system used in a data center, carrier, or enterprise, asystem composed of many devices (server and other computers, networkdevices such as routers, network switches, and load balancers, diskarrays and other storage systems, etc.) is run by intricate cooperationof the devices, a management server (a computer which executesmanagement software) is employed to manage the system efficiently.

Configuration information of the devices which is basic information inmanagement of the system performed by the management server is updatedmanually when there is a change in the devices.

Manually inputted configuration information has to be checked for itscorrectness to eliminate typing errors and the like. This is a problemfor middle to large-sized data centers since finding out of the manydevices the one that has been modified takes a lot of labor.

Automatic system configuration information collection has been proposedto reduce the labor of manually updating configuration information. Oneof known techniques of automatically collecting system configurationinformation is to scan the entire network of a data center to find anewly added device (US 2003/9551 A).

SUMMARY

In US 2003/9551 A, a new device is found by its IP address. If a wrongIP address is set to a newly added device, incorrect configurationinformation is created. In addition, it is very difficult to tellwhether a device added to the system is correct or not despite thedevice having a wrong IP address.

Maintenance of devices in a data center requires detailed configurationinformation including physical connection locations of the devices, forexample, which device is connected to which port of which networkswitch. The technique according to US 2003/9551 A is incapable ofspecifying a physical connection location. Therefore a system employingthe technique still needs manual input of connection locationinformation of a device that has undergone a change, and it does nothelp in saving labor.

Furthermore, in a large-sized data center whose network covers a widearea, it takes long to scan the entire network one round and captureconfiguration information according to US 2003/9551 A. Scanning theentire network also increases network traffics of a data center,weighing down the network bandwidth which is to be used for the originaloperation.

This invention has been made in view of the problems described above,and it is therefore an object of this invention to provide a method ofautomatically detecting addition, removal and other changes in a numberof devices constituting a system and managing physical connectionlocations of the devices by obtaining detailed system configurationinformation.

This invention detects the physical connection location of a hostcomputer, or network device, connected to a network device that is to bemonitored and collects a first identifier which is globally unique toone equipment of this host computer or network device connected to thenetwork device to be monitored (no two equipments share the same firstidentifier). System configuration information is created from thephysical connection location and the first identifier.

As a new device (host computer or network device) is connected to anetwork device to be monitored, the physical connection location of thenew device is detected, a first identifier globally unique to equipmentof the device in the detected connection location is collected, andconfiguration information is created from the physical connectionlocation in the network device and from the first identifier. Thisinvention can thus automatically detect a device added to a system, andis capable of correctly recognizing the physical location of the addeddevice and identifying the added device. This makes it possible to judgequickly and easily whether the added device is correct or not, and tomanage quickly and easily the system configuration of a data center thatis constituted of many devices.

Moreover, with device's connection location and details of individualdevices recognized, this invention can point out human error in adding adevice, changing a connection, and the like promptly and with precision,and accordingly can improve the efficiency of maintenance work in thedata center.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram showing the configuration of a data center.

FIG. 2 is an explanatory diagram showing a port table.

FIG. 3 is an explanatory diagram showing a MAC address table.

FIG. 4 is an explanatory diagram showing an ARP table.

FIG. 5A is an explanatory diagram showing a management table.

FIG. 5B is an explanatory diagram showing a device management table.

FIG. 6 is a sequence diagram for communications between a managementserver, a network switch, a server to be added, and a default gatewaythat is set to a server S3 in advance.

FIG. 7 is a flow chart showing an example of processing executed by themanagement server.

FIG. 8 is an explanatory diagram showing a configuration informationdisplay example.

FIG. 9 is a flow chart showing an example of processing executed by theserver S3.

FIG. 10 is a sequence diagram for communications between a managementserver, a network switch, a server to be added, and a default gatewaythat is set to the server S3 in advance according to a second embodimentof this invention.

FIG. 11 is a flow chart showing an example of processing executed by themanagement server.

FIG. 12 is a sequence diagram for communications between a managementserver, a network switch, and a server to be added according to a thirdembodiment of this invention.

FIG. 13 is a flow chart showing an example of processing executed by themanagement server.

FIG. 14 is a system diagram showing the configuration of a data centeraccording to a fourth embodiment of this invention.

FIG. 15 is an explanatory diagram showing a management table.

FIG. 16 is a sequence diagram for communications between a managementserver, a network switch, a server to be added, and a load balancer.

FIG. 17 is a flow chart showing an example of processing executed by themanagement server.

FIG. 18 is an explanatory diagram showing a display example of a displayon which devices grouped into VLAN groups are displayed.

FIG. 19 is an explanatory diagram showing another display example inwhich a VLAN group of a server S5 is moved from a pool to an operationA.

FIG. 20 is a flow chart showing an example of processing executed by themanagement server.

FIG. 21 is an explanatory diagram showing a display example in which aVLAN group of a server S2 is moved from the operation A to the pool.

FIG. 22 is a flow chart showing an example of processing executed by themanagement server.

FIG. 23 is a flow chart showing an example of processing executed by themanagement server for when this invention is applied to an existingsystem.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of this invention will be described below with referenceto the accompanying drawings.

FIG. 1 shows an example of the data center configuration. Servers S1through S3, a network switch 6, a DHCP server 3, and a load balancer 4are connected to a network switch 2 to constitute a system. The serversS1 through S3 execute an application or applications. The network switch6 connects other servers or the like to the system. The DHCP server 3lends each device an IP address. The load balancer 4 is connected toInternet 5 to adjust the load of the intra network servers S1 throughS3. The network switches 2 and 6, the load balancer 4 and others arenetwork devices of the data center while the servers S1 through S3 andthe DHCP server 3 are host computers.

A management server 1 which manages the above-described servers, loadbalancer 4 and network switches 2 and 6 is connected to the networkswitch 2 via an intra network (e.g., a LAN such as Ethernet). Themanagement server 1 executes management software to manage the system inthe data center which is composed of the devices and the intra network.Other than a LAN, a serial interface such as RS232C may be employed toconnect the management server 1 to the network switches 2 and 6.

The management software is executed in the management server 1 tomonitor the devices that are monitoring subjects (for example, theservers S1 through S3, the network switch 2, and the load balancer 4).

The management server 1 comprises a CPU, a memory, an external storagesystem, and an interface (omitted from the drawing) to execute themanagement software. The management server 1 also has a display 11,which displays the management status, and a keyboard and a mouse (notshown).

The network switch 2 has plural (n) ports P1 to Pn. The managementserver 1 is connected to the port P11. The DHCP server 3 is connected tothe port P12. The load balancer 4, which functions as a gateway to theintra network, is connected to the port P13. The server S1 is connectedto the port P1. The server S2 is connected to the port P2. The cascadednetwork switch 6 is connected to the port Pn. A broken line is drawnbetween the port P3 and the server S3 in FIG. 1 to indicate that theport P3 and the server S3 are not connected to each other yet.

The server S1 has an IP address (IP1 in the drawing) leased by the DHCPserver 3. A network interface (not shown) of the server S1 has a MAC(Media Access Control) address (MAC1 in the drawing), which is aglobally unique identifier (no two equipments share the same address).Similarly, the server S2 has an IP address IP2 leased by the DHCP sever3 and a MAC address MAC2 is set to its network interface. The cascadednetwork switch 6 has an IP address IPn leased by the DHCP sever 3 and aMAC address MACn is set to its network interface. The server S3, whichis not connected yet, has no IP address but a MAC address MAC 3 is setto its network interface.

The network switch 2 has a port table 21, which shows whether devicesare connected to the respective ports P1 to Pn or not, a MAC addresstable 22, which shows the association between the devices connected tothe ports P1 to Pn and MAC addresses, and an ARP (Address ResolutionProtocol) table 23, which shows the association between the MACaddresses of the devices and IP addresses.

The network switch 2 also has a control unit and a storage system (RAMor the like) (not shown). The control unit monitors the communicationstate of the ports P1 to Pn, updates the port table 21, the MAC addresstable 22 and the ARP table 23, and stores the update in the storagesystem. The network switch 2 sends the contents of the tables inresponse to a request from the management server 1.

An example of the port table 21 is shown in FIG. 2. In FIG. 2, each rowof the port table 21 has a port number field (PORT), which holds a portnumber (1 through n), and a state field (STATE), which bears either “ON”or “OFF” to indicate the state of the corresponding port. “ON” indicatesthat a device is connected to this port while “OFF” indicates that nodevice is connected to this port. For instance, “ON” is set to the statefields corresponding to the port numbers 1 and 2 in the port table 21since the servers S1 and S2 are connected to the ports P1 and P2 of FIG.1, respectively, while “OFF” is set to the state field corresponding tothe port number 3 since no device is connected to the port P3.

The management server 1 detects a port to which a device is connected byreading the port table 21.

An example of the MAC address table is shown in FIG. 3. In FIG. 3, eachrow of the MAC address table 22 has a port number field (PORT), whichholds a port number (1 through n), and a MAC address field (MAC ADDR),which bears a MAC address unique to a device that is connected to thecorresponding port.

For instance, when the servers S1 and S2 respectively connected to theports P1 and P2 of FIG. 1 execute communication, the network switch 2extracts a sender MAC address from a sent packet and sets the sender MACaddress to the MAC address field (shown in FIG. 3) corresponding to theport number of the port from which the packet is sent, so the MACaddress MAC 1 (00:aa:bb:cc:dd:ee) of the server S1 is set to the addressfield for the port number 1 while the MAC address MAC2(00:aa:bb:cc:dd:ff) of the server S2 is set to the address field for theport number 2.

The management server 1 can detect the physical connection location of adevice (which device is connected to which port) by reading the MACaddress table 22. The MAC address, which is a globally unique identifier(no two equipments share the same address), enables the managementserver 1 to identify devices connected to the ports P1 to Pn with ease.

An example of the ARP table is shown in FIG. 4. In FIG. 4, each row ofthe ARP table 23 has an IP address field (IP in the drawing) and a MACaddress field (MAC ADDR in the drawing) to which a MAC address unique toa device that has the corresponding IP address is set.

For instance, when the servers S1 and S2 respectively connected to theports P1 and P2 of FIG. 1 communicate, the network switch 2 extracts asender MAC address and a sender IP address from a sent packet, and setsMAC1 (00:aa:bb:cc:dd:ee), which is the sender MAC address of the serverS1, and MAC2 (00:aa:bb:cc:dd:ff), which is the sender MAC address of theserver S2, to the MAC address fields, while setting IP1 (192.168.1.10),which is the sender IP address of the server S1, and IP2 (192.168.1.11),which is the sender IP address of the server S2, to the IP addressfields.

The management server 1 reads the ARP table 23 to grasp the associationbetween the MAC address, which is a physical identifier unique to eachdevice, and the IP address, which is a logical identifier uniquethroughout the intra network (an identifier on a network). From theassociation between the MAC address and the IP address, the managementserver 1 can recognize whether the added device is correct or not aswill be described later.

The network switch 2 always monitors the ports P1 to Pn to update theport table 21, the MAC address table 22, and the ARP table 23 as thoseexemplified above.

The management server 1 collects, as will be described later, the portnumber, the MAC address, and the IP address in the above-describedtables from the network switch 2, and creates a management table 12 asthe one shown in FIG. 5A.

The management table 12 stores on each row the obtained information,namely, the MAC address, the port number, the device name, the IPaddress, and the date and time of update, in the order stated. Stored onthe first row in FIG. 5A is the MAC address, port number, device name,and IP address of the server S1, which are MAC1, P1, N1, and IP1,respectively, and the last update time and date of the server S1.Information of other devices is sequentially stored on the subsequentrows.

Based on the management table 12, the management server 1 recognizes thephysical connection location (port number) of a device connected to thenetwork switch 2, and identifies the device (MAC address) and itslogical identifier (IP address).

The management server 1 updates, as a device is added or removed, themanagement table 12 by creating or deleting a row (entry) of the table.The system configuration information thus can be kept up to date.Although not shown in the drawing, the management server 1 has anothermanagement table 12 for the network switch 2 to keep track ofconfiguration information for every device in the intra network(sub-net, for instance).

The management server 1 also has a device management table 13, whichassociates the MAC address of a server in the system with a device name.The device management table 13 is shown in FIG. 5B and is created andmanaged by a system administrator. Each time a new server is introducedto the system, a MAC address, a device name (e.g., equipment managementnumber) N1, N2 or the like necessary for the administrator to recognizethe added server, and a device type TYPE1, TYPE2, or the like areinputted in an associated manner. The administrator manages equipmentsby device names.

A description will be given below on a procedure for the managementserver 1 to obtain device configuration information taking, as anexample the case in which the server S3 of FIG. 1 is added to the systemby being connected to the port P3 of the network switch 2.

FIG. 6 is a sequence diagram for communications between the managementserver 1, the network switch 2, the server S3 to be added, and a defaultgateway (for example, the load balancer 4) set to the server S3 inadvance.

First, the server S3 is physically connected to the port P3 of thenetwork switch 2 (the step S501). Upon addition of the server S3, thenetwork switch 2 which monitors the ports P1 to Pn updates the statefield in the port table 21 that corresponds to the port number 3 fromOFF to ON (the step S502).

The management server 1 executes polling at a given cycle (e.g., forevery few seconds) (the step S503) and obtains values of the tables 21to 23 from the network switch 2 (the step S504).

The management server 1 finds out addition of a new device connected tothe port P3 of the network switch 2 from the fact that the state fieldin the port table 21 of the network switch 2 that corresponds to theport number 3 has been changed from OFF to ON (the step S505). As thenew port is found, the management server 1 adds an entry for the port P3to the management table 12. In the case where an existing port ischanged from ON to OFF, the management server 1 deletes the entry of themanagement table 12 that corresponds to the port number of this port.

The newly added server S3 requests an IP address from the DHCP server 3(the step S506). The DHCP server 3 sends in response a given IP address(IP3) to the server S3, which sets the received IP address IP3 as itsown IP address (the step S507). It is not always necessary to obtain anIP address from the DHCP server but instead an IP address may be set inadvance to a server to be added. In this case, the steps S506 and S507are omitted and addition of the server is immediately followed by thestep S508 for a dummy communication.

Obtaining the IP address, the added server S3 issues a dummycommunication to the given default gateway (load balancer 4) throughprocessing described later (the step S508). Since the server 3 is yet toobtain the MAC address of the default gateway (load balancer 4) at thispoint, the server S3 broadcasts an ARP request within the sub-net. Thedummy communication may not always be ARP access to the default gatewayand may be arbitrary access to an arbitrary server (PING, for example).

The default gateway sends an ARP in response to the ARP request tonotify the server S3 of the MAC address of the default gateway (the stepS509).

From a packet of the dummy communication by the server S3 in the stepS508, the network switch 2 which monitors the ports P1 to Pn extractsthe MAC address and IP address of the server S3, adds the MAC address ofthe server S3, namely, MAC3, to the MAC address table, and adds the IPaddress of the server S3 that is associated with the MAC address MAC3,namely IP3, to the ARP table 23 (steps S510 and S511).

The management server 1 executes polling on the network switch 2 at agiven cycle (the step S512), and obtains the values of the tables 21 to23 (the step S513). Then the management server 1 compares the obtainedvalues against the management table 12 to find, in the MAC address table22 and the ARP table 23, as a new device, MAC3 and IP3 corresponding tothe server S3 (the step S514).

The management server 1 searches the device management table 13 usingthe new MAC address and obtains the device name of the server (the stepS515).

The management server 1 adds the MAC address MAC3, the IP address IP3,and the obtained device name to the entry for the port P3 that has beencreated in the management table 12, and keeps configuration informationof the newly added server S3 (the step S516).

As has been described, through the periodical polling on the networkswitch 2, the management server 1 can detect a change in a device of theintra network and automatically update the management table 12. Thisenables the management server 1 to recognize the physical location of anew device and identify the device with the use of existing port numbersof the network switch 2 and the MAC address which is a globally uniqueidentifier, and to locate the logical position of the added device onthe network with the use of the IP address set to the added device.

The polling processing by the management server 1 which is shown in FIG.6 will be described next with reference to a flow chart of FIG. 7.

First, in a step S101, polling is performed on the network switch 2,which is a network device to be managed, and a transmission request ismade to the tables 21 to 23 to receive the values of the tables 21 to 23from the network switch 2.

In a step S102, the current management table 12 which holds the previousvalues is compared against the values in the tables 21 to 23.

In a step S103, the comparison results are used to judge whether thereis a change in link state of the ports P1 to Pn of the network switch 2or not. In the case where the ON/OFF state has been changed for any ofthe ports P1 to Pn, the procedure proceeds to a step S104 to add ordelete the entry for the corresponding port number. On the other hand,in the case where there is no change in link state, the procedureproceeds to a step S106.

In a step S105, the current date and time are stored as a time when thechange has happened.

In the step S106, the comparison results in the step S102 are used tojudge whether there is a new MAC address or not. When a new MAC addressis found, the obtained MAC address is added to the entry that has beenadded in the step S104. When there is no change in MAC address, on theother hand, the procedure proceeds to a step S109.

In a step S108, the device management table 13 is searched with theobtained MAC address to retrieve the name of the device newly added (thestep S515 of FIG. 6).

In the step S109, the comparison results in the step S102 are used tojudge whether there is a new IP address or not. When a new IP address isfound, the procedure proceeds to a step S110 to store this IP address.

In a step S111, whether or not there is a change in system configurationis judged. A change in system configuration advances the procedure to astep S112 while no change ends the processing.

In the step S112, which is reached by a change in system, the managementtable 12 is updated to reflect the above port number, MAC address, IPaddress, update time and date, and device name. In a step S113, thesecontents of the management table 12 are displayed on the display 11,where the configuration information for the newly added or deleted portnumber is highlighted.

When the server S3 is newly added as illustrated in FIG. 6, the aboveprocessing causes the display 11 of the management server 1 to displayconfiguration information as the one shown in FIG. 8.

FIG. 8 shows an example of configuration information displayed on thedisplay 11 of the management server 1 for when the server S3 is added tothe network switch 2 through the processing of FIGS. 6 and 7.

In FIG. 8, the state of the ports P1 to Pn of the network switch 2 isshown by a hatched square and a blank square. A hatched squarerepresents a port to which a device is connected while a blank squarerepresents a port to which no device is connected. A number displayedabove each square represents a port number.

Displayed below a port to which a device is connected is configurationinformation of the device.

Of the configuration information displayed, TYPE which indicates thetype of the device is put inside a square frame while the MAC address,the IP address, the device name, and the date and time of update areplaced under the frame.

For a while immediately after the server S3 is added, the configurationinformation displayed is framed and highlighted as shown in FIG. 8,thereby drawing attention to the device where a change has occurred andclearly signaling the administrator about the system having had change.The device type TYPE may be retrieved from the device management table13 of the management server 1 by storing MAC addresses and device typesin advance and by searching the table with the MAC address, or may beinputted by the administrator.

When the device type TYPE is switch, a button 121 is provided inside theframe as for the network switch 6 shown in FIG. 8 and is checked by themouse or the like to switch over to a configuration information screensimilar to the network switch 2.

FIG. 9 is a flow chart showing processing executed by the added serverS3 upon startup.

Immediately after connected to the network switch 2 and booted up, theserver S3 makes an ARP request and conducts a dummy communication with adevice at a given address (for example, a preset default gateway) inorder to cause the network switch 2 to obtain the MAC address and the IPaddress.

First, in a step S121, an IP address is requested from the DHCP server3. Once the IP address is obtained, the processing proceeds to a stepS122 to start a dummy communication with the default gateway. The dummycommunication is achieved, as shown in the step S508 of FIG. 6, bybroadcasting an ARP request packet within the sub-net, and enables thenetwork switch 2 to obtain the MAC address and IP address of the newlyadded server S3 instantly.

In a step S123, the server 3 then executes usual processing (forexample, startup of an application).

As has been described, according to the first embodiment of thisinvention, the management server 1 which manages a number of servers andnetwork devices in a data center or the like executes polling on thenetwork switch 2, which is a subject to be managed, making it possibleto automatically detect addition of a new device or removal of anexisting device for each of the ports P1 to Pn, and to manage deviceswith the MAC address (layer 2 identifier), which is a globally uniqueidentifier, and an IP address (layer 3 identifier) unique throughout theintra network. Therefore the physical location and logical position of adevice can be specified automatically and accurately.

With the MAC address, IP address, and device name of a device that islocated at a port of the network switch 2 displayed on the display 11 ofthe management server 1 to the administrator for a visual check, theadministrator can quickly and readily grasp the physical connectionlocation of a device where a change has occurred and the device'slogical position in the network. The administrator is thus freed fromthe hassle of manually checking the added or removed device unlike priorart. As a result, work steps accompanying a device change are greatlyreduced in number and the efficiency of system management is improvedconsiderably.

Whether the added device is correct or not can easily be judged by theMAC address which is an identifier unique to a device. Furthermore,whether the IP address set to the added device is correct or not canalso be judged with ease by comparison of the MAC address and the IPaddress.

For instance, in the case where the network switch 2 groups VLANs(Virtual LANs) by port locations and accordingly the port location of adevice added matters, the management server 1 can obtain, immediatelyafter a device is added, the port location and the MAC address or the IPaddress and can quickly judge whether the physical location and logicalposition of the added device are correct. The management server 1 ofthis invention is thus very effective in an application where VLANs aregrouped by port locations of the network switch 2.

Moreover, since the connection location of a device and details ofindividual devices are recognized, human error in adding a device,changing a connection, and the like can be pointed out promptly withprecision, and the efficiency of maintenance work in the data center canbe markedly improved.

The servers S1 through S3 constituting the system conduct a dummycommunication immediately after being booted up. This enables thenetwork switch 2 to quickly obtain the MAC address and IP address of anew device from an ARP request packet, thereby shortening the time ittakes for the management server 1 to recognize the device since additionof the device to the system and making instant comprehension of a changein system configuration possible.

Examples of dummy communication startup methods are shown below.

-   (1) Methods to conduct a dummy communication upon booting up the    server

(1-1) A method of starting up a dummy communication by BIOS, EFI(Extensible Firmware Interface), or other programs that operate beforeboot-up of the OS

(1-2) A method of starting up a dummy communication by a boot-up script(rc or the like) of the OS

(1-3) A method of conducting a dummy communication by an agent programwhich is activated after boot-up

-   (2) Methods to start up a dummy communication at regular intervals

(2-1) A method of starting up a dummy communication at regular intervals(for example, once a minute) by an agent program on a server

Furthermore, displaying devices that are connected to the network switch2 which is a subject to be managed and highlighting or otherwiseenhancing a newly added device as shown in FIG. 8 enable theadministrator to easily recognize the port location and device where achange has occurred and thus improve the system management response.

The management server 1 executes polling on the network switch 2 whichis a subject to be managed. Compared to scanning the entire network asin prior art, this embodiment can reduce traffics in the networkconsiderably and can obtain device configuration information withoutweighing down the network bandwidth.

FIGS. 10 and 11 show a second embodiment of this invention in which thepolling by the management server 1 of the first embodiment is replacedwith notification of a change in the ports P1 to Pn to the managementserver 1 by the network switch 2. The rest of the configuration of thesecond embodiment is the same as the first embodiment.

FIG. 10 is a sequence diagram for communications between the managementserver 1, the network switch 2, the server S3 to be added, and a defaultgateway (for example, the load balancer 4) set to the server S3 inadvance for when the server S3 is added at the port P3 of the networkswitch 2 shown in FIG. 1.

The network switch 2 has a control unit and a storage system (RAM or thelike) (not shown). The control unit includes monitoring module whichmonitors the ports P1 to Pn to update the port table 21, the MAC addresstable 22, and the ARP table 23, and notifying module which notifies themanagement server 1 of a change in the ports P1 to Pn. The storagesystem stores the port table 21, the MAC address table 22, and the ARPtable 23 as in the first embodiment.

First, the server S3 is physically connected to the port P3 of thenetwork switch 2 (a step S601). Upon addition of the server S3, thenetwork switch 2 which monitors the ports P1 to Pn updates the statefield in the port table 21 that corresponds to the port number 3 fromOFF to ON (a step S602).

The network switch 2 notifies the management server 1 of the change instate of the port P3.

Receiving the notification, the management server 1 recognizes additionof a new device at the port P3 of the network switch 2 from the factthat the state of the port number 3 of the network switch 2 has changedfrom OFF to ON (a step S604). As the new port is recognized, themanagement server 1 adds an entry for the port P3 to the managementtable 12 shown in FIG. 5A.

The newly added server S3 requests an IP address from the DHCP server 3(a step S605). The DHCP server 3 sends in response a given IP address(IP3) to the server S3, which sets the received IP address IP3 as itsown IP address (a step S606).

Obtaining the IP address, the added server S3 issues a dummycommunication to the given default gateway (load balancer 4) throughprocessing described in the first embodiment with reference to FIG. 7 (astep S607). Since the server 3 is yet to obtain the MAC address of thedefault gateway (load balancer 4) at this point, the server S3broadcasts an ARP request within the sub-net.

The default gateway sends an ARP in response to the ARP request tonotify the server S3 of the MAC address of the default gateway (a stepS608).

From a packet of the dummy communication by the server S3 in the stepS608, the network switch 2 which monitors the ports P1 to Pn extractsthe MAC address and IP address of the server S3, adds the MAC address ofthe server S3, namely, MAC3, to the MAC address table, and adds the IPaddress of the server S3 that is associated with the MAC address MAC3,namely IP3, to the ARP table 23 (steps S609 and S610).

The network switch 2 notifies the management server 1 that the MACaddress and IP address of the server S3 connected to the port P3 areobtained (a step S611).

The management server 1 receives the MAC address and the IP address (astep S612), and searches the device management table 13 to obtain thedevice name that is associated with the new MAC address MAC3 (a stepS613).

The management server 1 adds the MAC address MAC3, the IP address IP3,and the obtained device name to the entry for the port P3 that has beencreated in the management table 12, and keeps configuration informationof the newly added server S3 (a step S614).

Thus notified by the network switch 2 of the number of a port where achange has occurred along with the MAC address and IP address of thedevice connected to the port each time there is a change in state of theports P1 to Pn, the management server 1 can detect a change in a deviceof the intra network and automatically update the management table 12without conducting the polling of the first embodiment. This enables themanagement server 1 to recognize the physical location of a new deviceand identify the device with the use of existing port numbers of thenetwork switch 2 and the MAC address which is a globally uniqueidentifier, and to locate the logical position of the added device onthe network with the use of the IP address set to the added device.

FIG. 11 is a flow chart showing the processing contents of themanagement server 1 which have been described with reference to FIG. 10.

This flow chart is a modification of the flow chart shown in FIG. 7 inaccordance with the first embodiment, and has a step S131, in whichwhether a notification from the network switch 2 is received or not isjudged, in place of the step S101 for the polling processing. The restof the configuration of FIG. 11 is the same as FIG. 7, except that thestep S111 of FIG. 7 is unnecessary in FIG. 11 and accordingly iseliminated.

Receiving a notification from the management server 1 (the step S131),the management server 1 compares the contents of the current managementtable 12 against the contents of the notification and executes the stepS103 and the subsequent processing.

When the network switch 2 notifies that there is a change in port state(the step S603 of FIG. 10), an entry is added or deleted in themanagement table 12 and the time when the change has occurred is storedin the step S103 through S105.

As a MAC address and an IP address are notified from the network switch2 (the step S611), the MAC address is added to the entry of themanagement table 12 and a device name that is associated with the MACaddress is obtained (the steps S106 through S108). The IP address, thedevice name, and the update time are added to this entry and thendisplayed on the display 11 (the steps S112 and S113).

With the polling processing eliminated, the management server 1 canreduce traffics in the network even more than in the first embodiment.

FIGS. 12 and 13 show a third embodiment of this invention in which themanagement server 1 executes a PING (Packet Internet Groper) scan withinthe sub-net to which the network switch 2 belongs instead of having thenetwork switch 2 obtain the MAC address and IP address of the server S3through a dummy communication of the server S3 as in the firstembodiment. The rest of the configuration of the third embodiment is thesame as the first embodiment.

FIG. 12 is a sequence diagram for communications between the managementserver 1, the network switch 2, and the server S3 to be added for whenthe server S3 is added at the port P3 of the network switch 2 shown inFIG. 1.

First, the server S3 is physically connected to the port P3 of thenetwork switch 2 (a step S701). Upon addition of the server S3, thenetwork switch 2 which monitors the ports P1 to Pn updates the statefield in the port table 21 that corresponds to the port number 3 fromOFF to ON (a step S702).

The management server 1 executes polling at a given cycle (e.g., forevery few seconds) (a step S703) and obtains values of the tables 21 to23 shown in FIGS. 2 to 4 from the network switch 2 (a step S704).

The management server 1 finds out addition of a new device connected tothe port P3 of the network switch 2 from the fact that the state fieldin the port table 21 of the network switch 2 that corresponds to theport number 3 has been changed from OFF to ON (a step S705). As the newport is found, the management server 1 adds an entry for the port P3 tothe management table 12.

The newly added server S3 requests an IP address from the DHCP server 3(a step S706). The DHCP server 3 sends in response a given IP address(IP3) to the server S3, which sets the received IP address IP3 as itsown IP address (a step S707).

Next, the management server 1 executes a PING scan for each IP addressin the sub-net to which the network switch 2 belongs (own sub-net) inorder to make the network switch 2 recognize the MAC address and IPaddress of the added server S3 (a step S708).

The added server S3 responds to PING of the management server 1 (a stepS709). Using the PING response, the network switch 2 extracts the MACaddress and IP address of the added server S3, adds the MAC address ofthe server S3, namely, MAC3, to the MAC address table, and adds the IPaddress of the server S3 that is associated with the MAC address MAC3,namely IP3, to the ARP table 23 (steps S710 and S711).

The management server 1 executes polling on the network switch 2 at agiven cycle (a step S712), and obtains the values of the tables 21 to 23(a step S713). Then the management server 1 compares the obtained valuesagainst the management table 12 to find, in new entries of the MACaddress table 22 and the ARP table 23, as a new device, MAC3 and IP3corresponding to the server S3 (a step S714).

The management server 1 searches the device management table 13 toretrieve a device name that is associated with the new MAC address MAC3(a step S715).

The management server 1 adds the MAC address MAC3, the IP address IP3,and the obtained device name to the entry for the port P3 that has beencreated in the management table 12, creates configuration information ofthe newly added server S3, and updates the management table (a stepS716).

As has been described, the management server 1 executes periodicalpolling on the network switch 2 and, when there is a change in state ofa port of the network switch 2, executes a PING scan to make the networkswitch 2 recognize the MAC address and IP address of the new device, andthen obtains from the network switch 2 the MAC address and IP address ofthe added device. The management server 1 thus can quickly detect achange in a device of the intra network and automatically update themanagement table 12. This enables the management server 1 to recognizethe physical location of a new device and identify the device with theuse of existing port numbers of the network switch 2 and the MAC addresswhich is a globally unique identifier, and to locate the logicalposition of the added device on the network with the use of the IPaddress set to the added device.

The processing by the management server 1 which is shown in FIG. 12 willbe described next with reference to a flow chart of FIG. 13.

First, in a step S141, polling is performed on the network switch 2,which is a network device to be managed, and a transmission request ismade to the tables 21 to 23 to receive the values of the tables 21 to 23from the network switch 2 (the steps S703 and S704 of FIG. 12).

In a step S142, the current management table 12 which holds the previousvalues is compared against the values in the tables 21 to 23.

In a step S143, the comparison results are used to judge whether thereis a change in link state of the ports P1 to Pn of the network switch 2or not. In the case where the ON/OFF state has been changed for any ofthe ports P1 to Pn, it is judged that the link state has been changedand the procedure proceeds to a step S144 to add or delete the entry forthe corresponding port number. The link state is judged as changed whenON is set for a port number that is not listed in the current managementtable 12 and when no MAC address or IP address is stored in associationwith the port number added to the management table 12. On the otherhand, in the case where there is no change in link state, the procedureproceeds to a step S149, where a MAC address change is checked.

When there is a change in link state, a PING scan is executed in thesub-net to which the network switch 2 belongs through a loop of stepsS144, S145, and S145. The PING scan is executed sequentially from 1 to254 of the sub-net, for example.

In the step S145, the IP address in the PING response is comparedagainst the IP address in the management table 12 to judge whether thereis a new IP address or not. When a new IP address is found, theprocessing proceeds to a step S147 and, when there is no new IP address,the processing proceeds to a step 146 where it is judged whether thelast destination IP address has been reached or not. When this IPaddress has been reached, the processing ends and, otherwise, theprocessing returns to the step S144 to continue the PING scan.

In the step S147, the new IP address is stored. In a step S148, thecurrent time is stored as update time.

In the step S149, the table values of the network switch 2 which havebeen read in the step S141 are compared against the current managementtable 12 to judge whether there is a new MAC address or not. When thereis a new MAC address, the processing proceeds to a step S150. When thereis no new MAC address, on the other hand, the processing ends at thispoint.

In the step S150, the new MAC address is added to the entry whichcorresponds to the port number and which has been added in the stepS143. In a step S151, a device name associated with the new MAC addressis obtained (the step S715 of FIG. 12).

In a step S152, the IP address stored in the step S147, the update timestored in the step S148, and the device name obtained in the step S151are added to the management table 12 to which the MAC address has beenadded in the step S150.

In a step S153, the contents of the management table 12 are displayed onthe display 11, where configuration information for the newly added ordeleted port number is highlighted.

The above processing is repeatedly executed at a given cycle to find,when a change in state of a port of the network switch 2 is detectedthrough the polling processing, a new IP address through a PING scan andthe network switch 2 extracts the new IP address and MAC address fromthe PING response.

The management server 1 reads a new MAC address through the next roundof polling processing and records configuration information on the newlyadded server S3 in the management table 12. To be more specific, theport number, the IP address, and the modification time are obtained inthe first polling processing while the MAC address and the device nameare obtained in the next polling processing.

Having no need for dummy communication processing of the servers S1through S3 unlike the first embodiment, the third embodiment isadvantageous in that a new device can quickly be added to the system.

In the PING scan described above, PING for existing IP addresses listedin the management table 12 can be omitted and accordingly traffics inthe sub-net are reduced.

FIGS. 14 to 22 show a fourth embodiment of this invention in which thenetwork switch 2 of the first embodiment is modified to controlcommunications for VLANs separately by setting VLANs in accordance withan instruction from the management server 1, and in which the loadbalancer 4 of the first embodiment is modified to adjust the load ofVLANs separately. The rest of the configuration of the fourth embodimentis the same as the first embodiment.

FIG. 14 shows an example of the data center configuration. In FIG. 14,three VLANs are set to the network switch 2 based on an instruction fromthe management server 1, and the servers S1 through S4 are connected torespective VLAN groups. The description given here takes as an examplethe case in which a VLAN is controlled on the MAC address basis.

The load balancer 4 which serves as a gateway adjusts the load of VLANgroups separately in accordance with an instruction from the managementserver 1.

The network switch 2 controls a VLAN 201 composed of the servers S1 andS2, which execute an application A, a VLAN 202 composed of the serversS3 and S4, which perform an application B, and a pool VLAN 203 to putaside a server that is not assigned to any application.

The servers S1 through S4 are connected to the ports P1 to P4 of thenetwork switch 2, respectively. The MAC addresses MAC1 and MAC2 of theservers S1 and S2 are allocated to the VLAN 201 for the application Awhile the MAC addresses MAC3 and MAC4 of the servers S3 and S4 areallocated to the VLAN 202 for the operation B. The server S5 in FIG. 14is not connected to the network switch 2.

As in the first embodiment, the management server 1 has a managementtable 120 which manages the MAC address and the IP address for each portof the network switch 2. The management table 120 has, as shown in FIG.15, VLAN groups G1 and G2 in addition to the items of the managementtable of the first embodiment which is shown in FIG. 5.

The management server 1 has the device management table 13 as in thefirst embodiment.

The management server 1 monitors, through polling processing, a deviceconnected to the network switch 2 as in the first embodiment and, inaddition, when a new device is found, adds the device found to the poolVLAN 203 first and then to other VLANs following an instruction from theadministrator or operator.

FIG. 16 is a sequence diagram for communications among the managementserver 1, the network switch 2, the server S5 to be added, and the loadbalancer 4 for when the server S5 is added to the system in FIG. 15 andconnected to the port P5.

Steps S501 through S507 of FIG. 16 are the same as the steps S501through S507 of FIG. 6 described in the first embodiment. When the portP5 to which a new device is connected is found, an entry for the portnumber 5 is added to the management table 120, and the MAC address(MAC5), IP address (IP5), and device name of the new device are obtainedin a manner similar to the first embodiment (the steps S501 throughS515).

Thereafter, the management server 1 instructs the network switch 2 toadd the MAC address (MAC5) of the new device to the pool VLAN 203 (astep S801). The server S5 is thus added to the pool VLAN 203. Similarly,the load balancer 4 too is notified of the addition of the server S5 tothe pool VLAN 203 (a step S802).

The obtained MAC address, IP address, and device name are added to theadded entry of the management table 120 to create new configurationinformation.

As has been described, the management server 1 automatically adds a newdevice to the pool VLAN 203 in preparation of adding the new device toother VLANs.

The processing by the management server 1 which is shown in FIG. 16 willbe described with reference to a flow chart of FIG. 17. In the flowchart of FIG. 17, steps S101 through S111 are the same as the steps S101through S111 of FIG. 7 described in the first embodiment; when a newdevice (the server S5) is found, an entry is added to the managementtable 120 and the MAC address, IP address, and device name of the addeddevice are obtained.

In the case where a system configuration change is found in the stepS111, the management server 1 instructs the network switch 2 to add thenew server S5 to the pool VLAN 203 in a step S160. The management server1 then notifies the load balancer 4 of the addition of the server S5 tothe pool VLAN 203 to adjust the load for the VLAN groups separately (astep S161).

The obtained MAC address, IP address, device name, update time, and VLANgroup are added to the added entry to update the management table 120(the step S161). The devices are grouped into the VLAN groups anddisplayed on the display 11 of the management server 1 as shown in FIG.18 (a step S162).

FIG. 18 is a display example of the display 11 on which devices groupedinto VLAN groups are displayed.

The display 11 displays graphs which show time-series changes of theload factor of the servers S1 through S5 while dividing the servers intothe VLAN groups for pool, the application A, and the application B.

In FIG. 18, a symbol representing the server S5 newly added to the poolVLAN is highlighted in a frame to draw attention to the device change.Alternatively, configuration information may be displayed in associationwith the ports of the network switch 2 as shown in FIG. 8 in the firstembodiment. It is also possible to switch between the VLAN group-basisdisplay screen and the port-basis display screen.

Through the above processing, configuration information of a new deviceis collected as in the first embodiment and the added device is put inthe stand-by VLAN group (pool VLAN group). This facilitates maintenanceof a system that has a VLAN.

The graphs showing time-series changes of the load factor serve assymbols representing devices of the VLAN groups. This enables theadministrator to intuitively know to which group a new server is to beadded or which group has a server that can be removed and to make ajudgment concerning management quickly.

Described next is a case in which the server S5 of the pool VLAN 203 ismoved to other VLAN groups.

FIG. 19 shows a display example of the display 11 on which devicesgrouped into VLAN groups are displayed. In FIG. 19, the added server S5is moved from the pool VLAN 203 to the VLAN 201 for the application A.

The mouse (not shown) or the like of the management server 1 ismanipulated to move the symbol representing the server S5 (load factorgraph) from the pool group to the group for the application A.

With the manipulation of the mouse or the like, the management server 1instructs the network switch 2 to reallocate the MAC address of theserver S5 to the VLAN 201 for the application A as shown in a flow chartof FIG. 20 (a step S171). The-management server 1 notifies the loadbalancer 4 of the transfer of the server S5 from the pool VLAN 203 tothe application A VLAN 201 to change groups of load balancing (step S172to S173).

Then the VLAN group of the server S5 in the management table 120 ischanged from pool to application A to highlight the symbol of the serverS5 moved as shown in a frame in FIG. 19. Then, the processing ends.

Described next is the case of moving the server S2 of the VLAN 201 forthe application A to other VLAN groups.

FIG. 21 shows a display example of the display 11 on which devicesgrouped into VLAN groups are displayed. In FIG. 21, the server S2 thatis in execution in the application A group is moved from the VLAN 201 tothe pool VLAN 203.

The mouse (not shown) or the like of the management server 1 ismanipulated to move the symbol representing the server S2 from theapplication A group to the pool group.

With the manipulation of the mouse or the like, the management server 1instructs the load balancer 4 to remove the server S2 from the loadbalancing group for the application A as shown in a flow chart of FIG.22 (a step S181). Thereafter, the management server 1 instructs thenetwork switch 2 to reallocate the MAC address of the server S2 to thepool VLAN 203 (a step S182).

Then the VLAN group of the server S2 in the management table 120 ischanged from application A to pool, the symbol of the server S2 moved ishighlighted as shown in a frame in FIG. 21, and the processing ends (astep S183).

As has been described, configuration information of a new device(server) is created while the new device is added to the pool VLAN 203,which is a VLAN group assigned to no application, and then moved to anarbitrary VLAN group. Thus inconsistencies between a change in the loadbalancing group of the load balancer 4 and a change in the VLAN groupscan be avoided and a new device can be moved between VLAN groups quicklyand smoothly.

Although configuration information of a device connected to the networkswitch 2 is obtained by polling processing in the fourth embodiment ofthis invention, the fourth embodiment may be modified such that thenetwork switch 2 sends the configuration information actively or a PINGscan is executed as in the second or third embodiment.

In the fourth embodiment of this invention, an added server firstbelongs to the pool VLAN group to which no application is assigned.Alternatively, the added equipment may be directly assigned to aspecific application if the management server 1 has a table in which theMAC address of an equipment is associated with an operation to which theequipment is to be assigned (hereinafter referred to as operationreservation table). In this case, a step of reading the applicationreservation table to obtain a group or VLAN to which the added server isto belong has to be provided prior to the step S160 of FIG. 17 (thesteps S801 and 802 of FIG. 16). In the step S160, the server is added tothe VLAN of the designated operation or the load balancing group insteadof the pool VLAN or the load balancing group. Instead of designating anoperation using the MAC address, the IP address may be used to reserve adevice for an operation in the case where an IP address is set inadvance to each equipment. These functions make it possible toautomatically deploy a device for a designated operation by simplyadding the device to the network, and thus lighten the burden of thesystem administrator even more.

The above embodiments describe the operation of a system which ismanaged in accordance with this invention for when a new server is addedto the system. In contrast, the following fifth embodiment describes theoperation required apply management according to this invention to anexisting system to which management according to this invention has notbeen applied. To apply management by this invention to an existingsystem, the management server 1 has to recognize every network deviceand server connected to an existing network, and has to create theconfiguration management table 12 to display the configurationinformation.

In the existing system, processing has already been conducted andtherefore, enough communication has been executed between devicesconnected to the network. This eliminates such processing as dummycommunications for registering information of a new server added in themanagement table of the network switch 2. The management server only hasto read the management tables 21, 22, and 23 of the network switch 2 anduse the read information to recognize the system configuration.

FIG. 23 is a flow chart showing an example of processing executed by themanagement server for when this invention is applied to an existingsystem. The communication sequence in this case is exactly the same asthe communication sequence of FIG. 6 and others just after the datareading step (step 512) where polling is performed on the switch.Therefore, a communication sequence diagram for this embodiment isomitted.

In FIG. 23, the management server first reads the management tables 21,22, and 23 of the network switch 2 (a step S801). Based on the readinformation, the following processing is conducted:

One entry of the data of the port table 21 is obtained first (a stepS802). This is repeated until every data entry in the port table 21 isread (every port of the switch is examined) (a step S803).

When the link state of the corresponding port is ON, the followingprocessing is conducted (a step S804) (no processing is necessary whenthe link state is OFF):

First, an entry for the corresponding port is added to the configurationmanagement table 12 (a step S805). Update time is recorded (a step S806)and then the MAC address of a server connected to the corresponding portis obtained from the contents of the MAC address table 22 which havebeen read in the step S801 (a step S807). A device name is obtained fromthe corresponding MAC address entry in the device management table 13 (astep S808). An IP address associated with the MAC address in question isobtained from the contents of the ARP table 23 which have been read inthe step S801 (a step S809). The information obtained in the steps S806through S809 is written in the entry of the management table 12 that hasbeen added in the step S805 to complete the management table entry (astep S810). Lastly, information of the server in question is displayedon the console display 11 as shown in FIG. 8 (a step S811). In thisembodiment, server information displayed is not of a newly added serverbut of an existing server of the system, and therefore is nothighlighted.

Configuration information of the entire system is obtained by performingthe above processing on every switch in the system.

The above processing makes it possible to introduce a management systemof this invention into an existing system and to thereby recognize thesystem configuration. Once the system configuration is recognized inthis way, the system configuration can be managed by the methodsdescribed in the first through fourth embodiments.

Configuration information on a device of the intra network is obtainedby the management server 1 from the network switch 2 in the aboveembodiments. Equally detailed configuration information can be obtainedfrom another network device such as the network switch 6, the loadbalancer 4, or the router (not shown). Device suitable to this purposeis a network device capable of specifying the correlation between aphysical port and an identifier unique to one equipment such as the MACaddress, and between the MAC address and the IP address (identifier onthe network).

The above embodiments use the MAC address as a globally uniqueidentifier (no two equipments share the same address) but this inventionis not limited to the MAC address. Any identifier can be employed aslong as it is capable of specifying equipment (hardware). For example,UUID (Universally Unique Identifier), which is a device identifier fordiscriminating individual equipments in UPnP (Universal Plug & Play), ora processor serial number implemented to discriminate individual CPUsmay be employed.

Host computers in the above embodiments are servers. Storage systemssuch as disk arrays may also be included as host computers in managementof the system.

As has been described, a data center management method according to thisinvention is capable of automatically collecting the physical locationof a new device and its logical position such as an IP address to createconfiguration information of the device while keeping network trafficslow. The data center management method is thus applicable to amanagement system, a management software, or a management server whichmanages many servers in a data center or the like.

While the present invention has been described in detail and pictoriallyin the accompanying drawings, the present invention is not limited tosuch detail but covers various obvious modifications and equivalentarrangements, which fall within the purview of the appended claims.

1. A device management method for a data center having plural hostcomputers and network devices and a management module, the managementmodule monitoring the host computers and network devices to collectinformation on configurations of the host computers and network devices,the management module managing the host computers and network devicesbased on the collected configuration information, the method comprisingthe steps of: detecting a physical location of a host computer ornetwork device connected to a network device that is to be monitored;collecting a globally unique first identifier which is unique to a hostcomputer or network device equipment connected to the network device tobe monitored and is not shared by the equipments; and creating theconfiguration information from the first identifier and from thephysical connection location of the network device to be monitored,wherein the network device to be monitored connects the host computerswhile dividing the host computers into plural virtual networks, andwherein upon detecting addition of a new host computer to the networkdevice to be monitored, the management module adds the added hostcomputer to a virtual network previously set and chosen out of theplural virtual networks.
 2. The device management method for a datacenter according to claim 1, further comprising the steps of: collectinga network identifier given to a host computer or network deviceconnected to the network device to be monitored; and creating theconfiguration information from the first identifier, from the physicalconnection location of the network device, and from the networkidentifier.
 3. The device management method for a data center accordingto claim 1, wherein the management module requests, at a predeterminedcycle, the physical connection location, and the first identifier fromthe network device to be monitored.
 4. The device management method fora data center according to claim 1, wherein, when a change in connectionstate occurs, the network device to be monitored sends the physicalconnection location and the first identifier to the management module.5. The device management method for a data center according to claim 1,wherein the first identifier is collected after a host computer ornetwork device connected to the network device to be monitoredcommunicates voluntarily.
 6. The device management method for a datacenter according to claim 1, wherein the management module collects thefirst identifier after a network to which the network device to bemonitored belongs is scanned.
 7. The device management method for a datacenter according to claim 1, further comprising the step of obtaining adevice name of the host computer or network device using the firstidentifier, wherein the configuration information is created from thefirst identifier, from the physical connection location of the networkdevice, and from the device name.
 8. A device management server,comprising: a computer device; and a memory storing a program executableby the computer device, the program being comprised of a plurality ofmodules, said modules including: a configuration information collectingmodule, which monitors plural host computers and network devices in adata center and which collects information on configuration of the hostcomputers and network devices to be used in management of the hostcomputers and network devices; and a VLAN setting module which instructsthe network device to connect the host computers while dividing the hostcomputers into plural virtual networks, wherein the configurationinformation collecting module comprises: a location detecting modulewhich detects a physical connection location of a host computer ornetwork device connected to a network device that is to be monitored; afirst identifier collecting module which collects a globally uniquefirst identifier, which is unique to a host computer or network deviceequipment connected to the network device to be monitored and is notshared by the network device equipment; and a configuration informationcreating module which creates the configuration information from thefirst identifier and from the physical connection location of thenetwork device, wherein when the location detecting module detectsaddition of a new host computer to a network device to be monitored, theVLAN setting module adds the added host computer to a virtual networkpreviously set and chosen out of the plural virtual networks.
 9. Thedevice management server according to claim 8, wherein the configurationinformation collecting module comprises network identifier collectingmodule which collects a network identifier given to a host computer ornetwork device connected to the network device to be monitored, andwherein the configuration information creating module creates theconfiguration information from the first identifier, from the physicalconnection location of the network device, and from the networkidentifier.
 10. The device management server according to claim 8,wherein the location detecting module requests, at a predeterminedcycle, the physical connection location from the network device to bemonitored, and wherein the first identifier collecting module requests,after a new host computer or network device is detected, a firstidentifier from the network device.
 11. The device management serveraccording to claim 8, wherein the first identifier collecting modulecollects the first identifier after a host computer or network deviceconnected to the network device to be monitored communicatesvoluntarily.
 12. The device management server according to claim 8,wherein the first identifier collecting module collects the firstidentifier after a network to which the network device to be monitoredbelongs is scanned.
 13. The device management server according to claim8, further comprising device name collecting module which collects adevice name of the host computer or network device using the firstidentifier, wherein the configuration information creating modulecreates the configuration information from the first identifier, fromthe physical connection location of the network device, and from thedevice name.
 14. A device management system for a data center havingplural host computers and network devices which monitors the hostcomputers and network devices to collect information on configurationsof the host computers and network devices, and manages the hostcomputers and network devices based on the collected configurationinformation, the system comprising: a computer device; and a memorystoring a program executable by the computer device, the program beingcomprised of a plurality of modules, said modules including: a physicallocation detecting module which detects a physical location of a hostcomputer or network device connected to a network device that is to bemonitored; a first identifier collecting module which collects aglobally unique first identifier which is unique to a host computer ornetwork device equipment connected to the network device to be monitoredand is not shared by the network device equipment; and a configurationinformation creating module which creates the configuration informationfrom the first identifier and from the physical connection location ofthe network device to be monitored, wherein the network device to bemonitored connects the host computers while dividing the host computersinto plural virtual networks, and wherein upon detecting addition of anew host computer to the network device to be monitored, the managementmodule adds the added host computer to a virtual network previously setand chosen out of the plural virtual networks.
 15. The device managementsystem for a data center according to claim 14, further comprisingnetwork identifier collecting module which collects a network identifiergiven to a host computer or network device connected to the networkdevice to be monitored, wherein the configuration information creatingmodule creates the configuration information from the first identifier,from the physical connection location of the network device, and fromthe network identifier.
 16. The device management system for a datacenter according to claim 14, wherein the physical location detectingmodule requests, at a predetermined cycle, the physical connectionlocation from the network device to be monitored, and wherein the firstidentifier collecting module requests, after a new host computer ornetwork device is detected, a first identifier from the network device.17. The device management system for a data center according to claim14, wherein, when a change in connection state occurs, the networkdevice to be monitored sends the physical connection location to thephysical location detecting module and sends the first identifier to thefirst identifier collecting module.
 18. The device management system fora data center according to claim 14, wherein the first identifiercollecting module collects the first identifier after a host computer ornetwork device connected to the network device to be monitoredcommunicates voluntarily.
 19. The device management system for a datacenter according to claim 14, wherein the first identifier collectingmodule collects the first identifier after a network to which thenetwork device to be monitored belongs is scanned.
 20. The devicemanagement system for a data center according to claim 14, furthercomprising device name collecting module which collects a device name ofthe host computer or network device using the first identifier, whereinthe configuration information creating module creates the configurationinformation from the first identifier, from the physical connectionlocation of the network device, and from the device name.
 21. A programstored in a memory executable by a computer device for monitoring pluralhost computers and network devices in a data center and collectinginformation on configuration of the host computers and network devices,the program comprising: a location detecting module which detects aphysical connection location of a host computer or network deviceconnected to a network device that is to be monitored; a firstidentifier collecting module which collects a globally unique firstidentifier, which is unique to a host computer or network deviceequipment connected to the network device to be monitored and is notshared by the equipments; and a configuration information creatingmodule which creates the configuration information from the firstidentifier and from the physical connection location on the networkdevice; and a VLAN setting module which instructs the network device toconnect the host computers while dividing the host computers into pluralvirtual networks, wherein when the location detecting module detectsaddition of a new host computer to the network device to be monitored,the VLAN setting module adds the added host computer to a virtualnetwork previously set and chosen out of the plural virtual networks.22. The program according to claim 21, wherein the configurationinformation collecting module comprises network identifier collectingmodule which collects a network identifier given to a host computer ornetwork device connected to the network device to be monitored, andwherein the configuration information creating module creates theconfiguration information from the first identifier, from the physicalconnection location of the network device, and from the networkidentifier.
 23. The program according to claim 21, wherein the locationdetecting module requests, at a predetermined cycle, the physicalconnection location from the network device to be monitored, and whereinthe first identifier collecting module requests, after the locationdetecting module detects a new host computer or network device, a firstidentifier from the network device.
 24. The program according to claim21, wherein the first identifier collecting module collects the firstidentifier after a host computer or network device connected to thenetwork device to be monitored communicates voluntarily.
 25. The programaccording to claim 21, wherein the first identifier collecting modulecollects the first identifier after a network to which the networkdevice to be monitored belongs is scanned.
 26. The program according toclaim 21, further comprising device name collecting module whichcollects a device name of the host computer or network device using thefirst identifier, wherein the configuration information creating modulecreates the configuration information from the first identifier, fromthe physical connection location of the network device, and from thedevice name.